Performance improvements in solar flat plate collectors by integrating with phase change materials and fins: A CFD modeling

Performance of solar flat plate collectors can be improved by using phase change materials for latent thermal energy storage. In this study, a three dimensional transient CFD model is developed to investigate a solar flat plate collector integrated with a layer of PCM. Heat transfer and fluid dynamics are simulated in each component by numerical solving of energy and momentum equations. Fins are also incorporated into the PCM and the resulting temperature distributions are analyzed during two different summer and winter days in Shiraz, Iran. Four different types of PCM with various melting temperatures are considered in this research. Results show that although the system with PCM has lower output temperatures in the morning, hot water can be supplied in a longer duration in the evening while discharging. Also, the average collector efficiency is increased from 33% to 46% in the summer day for the PCM with minimum melting temperature. In addition, incorporation of fins increases the storage capacity especially in PCMs with higher melting temperatures. However, heat dissipation into the ambient is larger in the finned system during the discharge in the afternoon and can reduce the efficiency marginally. •CFD modeling of flat plate collectors integrated with PCM is presented.•Variable and realistic ambient conditions are considered continuously.•Transient 3D temperature and velocity distributions are calculated in different parts.•Different PCMs are studied in summer and winter weather conditions.•Effects of incorporation of fins into the PCM are studied.